Magneto-impulser.



Patented Dec 17 1918 2 SHEET$SHEET 1 I mum R K EVANS MAGNETO IMPULSER.

APPLICATION man JULY 29. me.

R. KfEVANS.

MAGNET'O IMPULSER.

APPLICATION FILED JULY 29.1918.

Pzitented Dec. 17, 1918.

2 SHEETSSHEET 2.

UNITED STATES PATENT ornrcn.

302mm) x. EVANS, or CHEBOYGAN, momeim, essronon are some r. o.s'mar'rox,

' or ELKHART, morons.

MAGNETO-IMPULSER.

Specification of Letters Patent. 1 Patented Dec. 17, 1918.

Application filed July 29, 1918. Serial No, 247,326.

of Gheboygan, in the county of Cheboygan and State of Michigan, haveinvented certain new and useful Improvements 1n Mag- .neto-Impnlsers;and I do hereby declare that the following is a full, clear, and ex-.act description thereof, reference being had late the accompanyingdrawings, and to the letters of reierencemarked thereon, which form apart of thisspecification.

My invention relates to mechanism for driving a magneto usedinconnection with internal combustion engines for producing the current toeffect the ignition of the charges in the engine, and relates moreparticularly to that class of mechanisms which operate to produce themaximum current flow or spark introduced into the cylinder or cylindersof the engine by means of a momentary acceleration of one of the movingparts of the magneto.

In starting a motor, the normal average sparking moment of the magnetoconnected therewith occurs when the crank of the piston compressing thegases in the cylinder is from zero to ten degrees ahead of the deadcenter on the upward stroke.

One of the objects of my invention, therefore, is to retard or arrestthe normal rotation of the armature in relation to the crank shaft,while the crank shaft continues to advance. and then to release thearmature at that minute element of time which intervcncs between theextreme moment of compression and the moment of explosion, so as toproduce not only the explosion or impulse at the correct time but alsoto produce the maximum current fiow or spark at that particular moment.

Another object of my invention is not only to produce the explosion orimpulse at the correct moment but predetermines the firing moment of themotor at all speeds under 180 R. l M.- regardless of any spark controlwhich may have been provided for the purpose of advancing or retardingthe tiring moment of the motor.

Another object is to eliminate all danger of backfire when the magnetois properly timcd with the motor so that the operator need give noattention to the position of the spark control when cranking the motor.

Another object is to provide a device which may be so adjusted that themotor and magneto may be properly timed for starting and for very lowspeed conditions and, which immediately upon the motor attaining a speedsufiicient for the impulser to become inoperative, the firing momentwill advance to any desired degree of angularity thereby providing amuch more desirable running condition of the motor without dependence onmanual operation.

In other words, one of the principal objects of my invention isto soregulate the mechanism with respect to the magneto as to produce themaximum spark at low speed at any desired moment of ignition.

Another object of my-invention is to automatically retard the spark whenit is in action by causing the armature to be at rest during the periodthat the driving shaft advances a predetermined annular distance, andthen releasing the armature and automatically causing it to advance toits. nor-.-

mal position in relation to the motor crank shaft under an acceleratedspeed; the moment of acceleration being fixed in relation to the desiredand predetermined moment of explosion in the cylinder on the compressionand explosion stroke. Thus, no matter when the firing moment of themotor may occur at all speeds under 180 R. P. M. re

gardless of any spark which may have been provided for the purpose ofadvancing or retarding the firing moment of the motor, it is the objectof my device to time the motor to fire at a position coinciding with thecorrect impulsing moment of the magneto.

It is desirable, in magnetos for multi 1e cylinder motors, that theimpulser act with each explosion stroke. It is one of the principalobjects of my invention, therefore, to provide a mechanism which inoperation will result in two impulses. for each revolution of themagneto shaft, each one corresponding to the two explosion strokes of afour cylinder motor. I

It is another object of my invention to produce a simple, durable,relatively cheap mechanical construction in a spark regulator andimpulser. for'the purposes above stated, in which all the working andfixed parts are contained within a casing or jacket, and in which theparts function automatically, so that the operator has only to apply,externally, the necessary power to rotate the magneto shaft,a mechanismwhich shall be so constructed as to produce the maximum of desiredresults with the minimum of vibration, jarring andwearing of the variousparts.

In the drawings:

Figure 1 is a perspective view of the easing of a magneto to .which myimproved (perspective view of a yoke by the rotatable driving Fig. 5 isa vertical, sectional view of the spark regulator and im ulser, takenupon the plane indicated by t e dotted line 55 of Fig. 2.

Fig. 6 is a view corresponding to that of Fig. 2 but taken upon theplane indicated by the sectional line 6-6 of Fi 5, and

' looking in the direction indicated y thenrows. v Fig. 7 is a sectionalview, taken on the plane indicated by the dotted line 7 7 of Fig. 5,looking in the direction indicated by the arrows.

Fig. 8 is a vertical, sectional view through i the tapered portion ofthe armature shaft 'and the bearing hub of the. driven member, showingmore clearly the integral lug and. its relation to a yielding member orspring .and showing also in dotted lines, the relative location on theopposite side of said driven member of the two awl members.

Beferringto that embo ime nt of my invention shown in the accompanyingdrawings, the casing A of the magneto contains the usual horse-shoemagnets, armature, and the like, not shown, and a journal bearin u forthe armature or magneto shaft B. he shaft B is preferably provided witha tapered portion 5 and a threaded end portion 7). (l is a. driveshattconnccted by suitable couplings D with the coupling D, the latterbeing secured to or integral with a rotatable driving member 10.

The stationary support 1, suitably secured tothe'magneto frame A, isprovided with an outwardly projecting, circular flange or wall 2. Uponthe inner faceof the support 1 is a cam member 3, suitably. secured byscrews t or otherwise in a predetermined position to said support. Arotatable driven member 5, of disk form, provided with an aperturedbearin hub 6, is secured to the armature shaft B y the key 7. As shownin the drawing, the aperture of the driven member 5 and a portion of thea erture of its bearing hub 6, are taperec to fit over thecorrespondingly tapered portion I) of the shaft B. A spanner lock nut 8,provided with a hub 9, is interiorly screw threaded for engagement withthe threaded 'end I) of the shaft, the diameter of thenut greater thanthe diameter of the end e hub bearing 6 so as to have overlappingengagement with the driving member 10. J The nut 8 being thus locked bythe screw threads onto the armature shaft and the driven member 5 andits hub 6 being keyed to said shaft, said three partsrotate together andat the same time the nut 8 bearing against the face of the drivingmember 10 holds the latter in place. In practice, I recommend a smallclearance, say .005 of an inch between the end of the hub 6 and theadjacent'surface of the nut B.

b fit The external diameter of the hub 9 issuch as to aiford bearingengagement thereof within the untapere the hub 6 of the driven member 5.

The driving member 10 is provided with an annular, upwardly extendingwall 11', which at its up r margin is exteriorly recessed at 12, so t atsaid wall 11 at its upper end will fit within and register with the wall2 of the sup ort 1, as clearly shown in Figs. 1 and 5. aid driven member10 is provided with an interior bearing 'hub 13, which is centrallyapertured to fit about and to have rotative, bearin engagement with thehub 6' Between the caring hub 13 and the circular wall 11, is an annularrecess, spanned at one portion only by a radial rib 14. This recessprovides space for the yielding member 15, which in the present instance=takes the form of a spiral spring. ()ne end of the spring 15 haspermanent bearing against one side or face of the radial rib 141. Thelength of the spring 15 is such that its other end would rest againstthe o posite side of said radial rib 14 and won d so rest, except forthe inter-position ofa movable lug 17 and a yielding stop or cushion 16which, in the present instance, takes the form of leather packing (seeFig. 7). Said big 17 is integral with or fixedly connected to the drivenmember 5, and extends from that face thereoffrom which the hearing hub 6extends.

.On. that side of .the driven member or disk 5, opposite that carryingthe lug 17, are two studs or pins 18, 18. Each of said pins afl'ords apivotal bearing support for a locking pawl 19, suitably apertured to fitover said pin. .Each pawl 19, at its outer end, is providedwith a lug20, adapted. to engage the cam 3. The cam 3 is provided on itsperipheral margin with a cut away apertured portion of lug 14.

portion 21 which terminates in a camshoulder 22. The lug 20 of the pawlis adapted, at certain periods in the movement hereinafter described, tofall into the outway portion 21 and to have locking engage ment with thecam shoulder 22, as clearly indicated in Figs. 2 and 6. i

23 is an apertured yoke, loosely and rotatively mounted upon a bearingshoulder 24 of the armature shaft bearing. Said yoke isvprovided Withradially, outwardly and diametrically oppositely extending arms 25, theouter ends of said arms are set in and have engagement with suitablerecesses 26 in the reduced end 12 of the Wall 11 of the drivingh'ie'mber 10.

The operation of my invention is as fol lows: the drive shaft C isrotated in the usual manner and, through the couplings D, D", thedriving member 10 is similarly rotated. Bythe engagement of the lug 17on the driven member 5 between the yielding or spring member 15 with thelug 14 and the interposed. cushion 16 (see Fig. 7), the driving anddriven members will be simultaneously rotated, until the outer end 2B ofone of the pawls 19, swinging upon its stud 18, drops into the cut-awayspace 21 of the fixed cam 3 and comes into contact with the eamsshoulder22. When the lug 20 is thus engaging the non-rotatable cam shoulder 22,and the driven member 5 is thus arrested, the rotary forward movement ofthe driving member 10 continues, though momentarily retarded in itsspeed by the resisting action of the spring 15 when compressed by thelug 17 against the radial The continued rotation of thedrivmg member 10,however, presently brings one of the arms 25 of the yoke 23 into aposition when the pawl 19 is lifted by said arm from the cam shoulder22. Thereupon the spring 15 Will immediately expand into its normalposition with the efiect of causin the momentarily retarded but nowreleased driven member 5 to again move forward in itspath of rotation,and with an accelerated motion, as compared with the speed of retationof the driving member 10; and thus, so to speak, catch up with thedriving member 10.

This momentary retarding of the forward movement of the driven member 5continues while the driving member 10 travels over an area of apparently32 degrees. Thus the current flow or spark is produced at the proper andpredetermined moment of time.

m'milar action takes place with respect to the secondpawl 19, as therevolution of the driving member IOrontinues. it will be understood thatWhile the driving member 10 is makinn one complete revolution. theretardinggand then the accelerated forward movement of the'driven memberand the magneto shaft will take place twice. There are tli'us producedtwo impulses for e single revolution of the shaft, COHQSQOHilL-fl; tothe two explosion strokes of a four cyhnder motor.

I have stated that one nit-the objects of my To invention is to providesuch an adjustment that the motor and magneto ma be properly timed forstarting and for very low speed conditions and this may be accomplishedby adjusting the position of? the '75 driven membewith respect to thearmature shaft, and having in mind the accurate relation of the lockingkey-Way of said shaft to the fixed cam. in practice, when an cillatingcircuit breaker is used with my invention, this adjustment may beeffected in the following manner:

The key-Way in the armature shaft will be milled in accurate relation tothe lined cam. The keywvuy in the driven member 5 is then cut in suchposition that the hi9: 2% of the pawl 19 will engage the cam shoulder atthe point at which the armature circuit breaker cam is 20 degrees beforethe position at which the circuit breaker will open at full advance, oron the peak of. the wave. it must be borne in mind that the .-:tan(lardrange of spark control adapted for couuuerc-ial use, and required by theGovernment, is 32 degrees, and this range starts the full advance orhigh wave position in the dirertion of rotation. it, for example, thecircuit breaker is set at er ll retard, it will be necessary to provide?that the impulse reach this point. in its forward travel. Therefore, byadding 32 degrees to the 20- degrees already allowed, and by adding;- (3degrees additional as a margin of safety to insure the circuit breakeralways opening, a range oi approximately 58 degrees is oh rained overwhich the impulser must operate. it ishighly desirable to a-fin the 21'?de- Qrees referred to ahead of the ful advance position, in order toinsure the armature against saturation when its rotation tarded. toallow for the armature havnr ficient speed in its impulse heifore cuitbreaker opens and to guard against any inaccuracies in time. i then"place ti 23 in such a position in the driving: member i i l0, that its"forward movement will c ul'i'nur through 68 degrees of rotation beforesaid yoke comes in contact with and the lug 20 from the cam shoulderThug 1 will be seen that the amount of impu the lugs and the yoke areoperatln I substantially correspond with the pos Ii 6 (a tne ew tion atwhich ircuit breaker will open when the impulser is not operating; theformer being: about (3 degrees later, on a perfect instru ment. The,momentof impulse may then be marked, one mark being: placed on astationary shell 1 and another mark on the driving member 10. The I'iyWheel of the motor is, then brought to a position at which it is I30open. a

desired to fire the motor when cranked, and the marks thus made shouldthen coincide and the driving coupling keyed to the drivin shaft.

pon cranking it will be found that the rotation of the armature shaftwill be inter- -rupted at a point 58 degrees before the mo- It Wlll alsobe found that the motor cannot fire in advance, as it has alreadyreached its firing position before the impulser is tripped. Thisoperation just described refers to the use of my impulser with anoscillating circuit breaker.

In its use with a fixed circuit breaker, the latter is made to break atthe peak of the wave and to secure anv desired position, it is onlynecessary to change the location of the key-way in the armature shaft inits relation to the predetermined position to fixed cam. Having alreadyexplained that 58 degrees is the correct wind or travel of assuming thatthe operator desires to run the motor to fire 12 degrees, for example,in advance of its firing moment in starting (subtracting the 12 degreesfrom the 58, leaving 46 degrees) he will key the armature shaft to thedriven member 5 in such position that the move ment of the armature willbe 46 degrees before the circuit breaker would normally the impulser,and

By timing the motor to fire at a position coinciding with the impulsinthe magneto, it will be found t iat when the motor reaches a speed atwhich-the impulser becomes inoperative, the motor will automaticallyadvance the desired 12 degrees. By thus adjusting the locking positionof the cam shoulder 22 with relation to the center and to the armature,the interruption of the forward movement of the armature is caused iotake. place at the desired, predetermined time. Thus the cam isinitially adjusted or set in a pre determined position on the support.

it will be noted that the form in which my invention is embodied, asabove described, is exceedingly simple, includes the fewest number ofparts, is positive and accurate in its operation, is substantially dustand fool proof, and that once adjusted it is not liable to get out oforder. Its efiiciency and durability are therefore limited only to thelength of normal wear and tear in use.

Slight modifications may, of course, be

driving moment of j the firing moment of member .in juxtapositiom arotatable magneto shaft, a stationary cam member in pixtapositlon tosaidshaft, a driving member, a driven member on said shaft, meansoperatively connecting the driving and driven members, said meansincluding means for accelerating the movement of the driven member,driven member adapted for ,engagement with the stationary cam member toretard the rotary movement of the driven member during a portion of itsmovement, and means located between member and in operative enga ementwith the driving member for releaslng the cam engaging means.

In a device of the character described, a rotatable magneto shaft, astationary cam member in juxtaposition to said shaft, a member, a drivenmember on said shaft, means operatively connecting the driving anddriven members, 1 said means including means for accelerating themovement of the driven member, means on the driven member adapted forengagement with the stationary cam member to retard the rotary movementofth'e driven member during a portion of its movement, and rotatablemeans in operative engagement with the driving member whereby the camengaging means on the driven memberwill the cam and. the driven means onthe be released from engagement with the cam member.

a rotatable magneto shaft, a stationary cam to said shaft, a drivingmember, a driven member upon and rotatable with said shaft, meansoperatively connecting the driving and driven members, said meansincluding means for automatically accelerating driven member, means onher adapted for automatic engagen'ient; the cam member to retard therotary move ment of the driven member during a portion of its movement,and means located between the cam and the driven member adapted torelease said cam engaging means.

the movement of the the driven memwith 4. In a device of the characterdescribed,

a support having shaft bearing, a rotatable magneto shaft, a hub on saidbearing, a stationary cam on the support, a driving member, a rotatabledriven member-within the driving membe gand secured to said shaft, meansoperatively connecting the driving extending operatively operativelyconnecting arm in operative engagement with the 50 with the cam,

and driven members, means on the driven member adapted for engagementwith the cam, and a yoke member rotatably mounted on said hub andprovided with a radially arm in operative engagement with the drivingmember and adapted to contact with the cam engaging means.

5. In a device of the character described, a support having shaftbearing, a rotatable 10 magneto shaft, a hub on said bearing, astationary cam ad]usted on the support in a predetermined position, adriving member, a rotatable driven member within the driving member andsecured to said shaft, means connecting the driving and driven members,means on the driven member adapted for engagement with the cam, and ayoke member rotatably mounted on said hub and provided with a radiallyex- 20 tending arm in operative engagement with the driving member andadapted to contact with the cam engaging means.

6. In a device of the character described, a support having shaftbearing, a rotatable 25 magneto shaft, a hub on said bearing, astationary cam adjusted in a predeterminedrelation on the support, adriving member, a rotatable driven member within the driving member andsecured to said shaft, means the driving and driven members, means .onthe driven member adapted for engagement with the cam, .a yoke membrotatably mounted on said hub and provided with a radially extenging1'1V- ing member and adapted to contact with the 'cam engaging means,and means for producing relative movement between the driving and drivenmembers and an accelerated 40 movement of the shaft when the camengaging means is released.

7. In a device ofthe character described, a support having shaftbearing, a rotatable magneto shaft, a hub on said bearing, a stationarycam adjusted in a predetermined relation on the support, a drivingmember, a rotatable driven member within the driving member and securedto said shaft, means on the driven member adapted for engagement a yokemember rotatably mounted on said hub and provided with a radiallyextending arm in operative engagement with thedriving member and adaptedto contact with the cam engaging means,

and means for producing relative movement between the driving and drivenmembers an an accelerated movement of the shaft when the cam engagingmeans is released, said means embracing a radial rib in the drivingmember, a lag on the driven member projecting within the driving memberand a yielding device interposed between the rib and the lug.

8. In a device of the character described, a

support having a shaft bearing, a hub on said bearing, a rotatablemagneto shaft in said bearing, a stationary cam on said support, arotatable driving member, a driven member on and rotatable with theshaft, a yoke member rotatably mounted on the bearing hub and positionedbetween the driven member and the cam. two radially projecting arms onthe yoke the ends of which are in operative engagement with the drivingmember, two cam engaging members pivotally mounted. diametrically on thedriven member adapted each in its turn to engage the cam, and meansoperatively connecting the driving and driven members adapted forproducing relative moven'ient between them.

9. In a device of" the character described, a support having a shaftbearing, a hub on said bearing, a rotatable magneto shaft in saidbearing, a stationary cam on said support, a rotatable driving member, adriven member on and rotatable with shaft a yoke member rotatablymounted on the bearing hub and positioned between the driven member andthe cam, two radially projecting arms on the yoke the ends of which arein operative engagement with the driving member, two cam engagingmembers pivotally mounted diametrically on the driven member adaptedeach in its turn to engage the cam, and means operativeiy connecting thedriving and driven members adapted for producing relative movementbetween them, twice in each revolution.

10. In a device of the character described, a support having a shaftbearing, a hub on said bearing, a rotatable magneto shaft in saidbearing, a stationary cam on said support, a rotatable driving member. adriven member on and rotatable with the shaft, a yoke member rotatablymounted on the bearing hub and positioned between the driven member andthe cam, two radially projecting arms on the yoke the ends of which arein operative engagement with the driving member, two cam'engagingmembers pivotally mounted diametrically on the driven member adaptedeach in its turn to engage thecam, and means operatively connecting thedriving and driven members adapted for producing relative movementbetween them, twice in each revolution and time during a travel ofapproximately 32 degrees,

11. In a device of the character described, a support, a rotatablemagneto shaft projecting therefrom, a stationary cam on said support, adriving shaft coupling in alinement with the magneto shaft, :1 drivingmember interposed between the shaft and said coupling, a driven memberon the shaft, means for operatively connecting the drii ing and drivenmembers, means on the driven member adapted UJ engage the cam, re easingmeans located between the driven ing a rotatable shaft, a cam member, asupport on the magneto for said cam member, a

' driving member on the shaft, a driven memher mounted on the shaft,means associated with said driven member to engage the cam member andretard the movement of the driven'member, means operatively connectingthe driving and driven members including means for accelerating themovement of the driven member upon its release, means located betweenthe cam and the driven memthe release of the cam engaging means shalloccur coincidentally with the high wave moment of the magneto.

In testimony, that I, claim the foregoing as my invention I. afiix my siature in the presence of two witnesses, this 13th day of July A D. 1918.

RONALD K. EVANS.

Witnesses:

WILLIAM L. MEALS, KARL W. Dorm.

